Is 3000 S Hospal a suitable dialyzer to shorten dialysis time schedule? A cooperative study on biofiltration.

The Biofilter 3000 S Hospal may combine higher convective clearance rates (Cc) with usual diffusive clearance rates (Cd) (i.e. similar to Cuprophan dialyzers), giving a higher total clearance rate (Ct) of small and middle molecules. Use of the Biofilter has been suggested to shorten dialysis time schedules. This study was carried out in 8 patients on RDT 3 times weekly, by cuprophan filter and acetate dialysis. The patients were shifted to dialysis with 3000 S guided by two principles: to shorten dialysis time by 1 hour per session, and to reinfuse 6 liters of bicarbonate-saline solution (40 mEq/l) per single dialysis. Besides the usual clinical and laboratory controls, in three patients clearance studies were carried out during four different dialysis sessions: Ct, Cc and Cd of urea K+, creatinine, uric acid and phosphate were measured. No change was observed in the main clinical and laboratory parameters after 3-5 months (average 3.9) of treatment with Biofilter 3000 S; in addition, serum alkaline phosphatase concentration decreased progressively. Clearance results, however, indicate that the expected high values of Ct do not occur, because Cd decreases as Cc is increased. A primary goal of research in hemodialysis is to reduce the average time of treatment while ensuring simultaneously "physiological" dialysis. A possible approach to this problem is to use dialyzers with highly permeable and biocompatible membranes such as the "biofilter" 3000 S Hospal.(ABSTRACT TRUNCATED AT 250 WORDS)